Host Spirochete Interactions in Lyme Disease

描述(申请人提供)：感染伯氏疏螺旋体导致莱姆病，这是美国主要的节肢动物传播的传染病。尽管这种疾病很普遍，但人们对这种感染的分子发病机制知之甚少。由于细菌对宿主组织的黏附被认为是致病过程的关键成分，因此我们建议进一步鉴定伯氏杆菌核心蛋白和BBK32粘附素分别与宿主核心蛋白和纤维连接蛋白结合的特征。对这些识别细胞外基质分子的硼质微生物表面成分的粘附性的表征将与研究一起进行，以解决粘附素基因已单独或联合被基因灭活的菌株的传染性。为了进一步研究伯氏杆菌脂蛋白粘附素及其突变体，我们提出了以下具体目标：(1)明确纤维连接蛋白结合BBK32在伯氏杆菌致病中的作用；(2)进一步表征核心蛋白结合蛋白在伯氏杆菌致病机制中的作用；以及(3)评估所选择的脂蛋白在伯氏伯氏杆菌感染的分子发病机制中的重要性。我们已经在基因上灭活了伯氏杆菌感染性分离株中的纤维连接蛋白结合粘附素，并有强有力的初步证据表明，纤维连接蛋白结合参与了二次定植和/或保护生物免受清除。该突变体代表了脂蛋白编码基因中第一个具有已知黏附活性的基因敲除，该基因以哺乳动物配体为靶标。对核心蛋白结合素结合蛋白粘附素的编码基因也计划进行类似的分析，并进行遗传学研究，以评估一组新的脂蛋白对疏螺旋体发病的重要性。在使用感染的体外相关性(即黏附和侵袭)进行初步特性研究之后，我们将确定这些黏附素在受感染的哺乳动物宿主体内定植、传播和/或持续存在的分子机制(S)。

DESCRIPTION (provided by applicant): Infection with Borrelia burgdorferi leads to Lyme disease, which is the leading arthropod-borne infectious agent in the United States. Despite the prevalence of this disease, little is understood about the molecular pathogenesis of this infection. Inasmuch as bacterial adherence to host tissues is recognized as a critical component of the pathogenic process, we therefore propose to further characterize the B. burgdorferi decorin binding and BBK32 adhesins that bind to host decorin and fibronectin, respectively. Characterization of the adhesive properties of these borrelial microbial surface components that recognize extracellular matrix molecules will be conducted in concert with studies to address the infectivity of strains whose adhesin genes have been genetically inactivated either individually or in combination. To further characterize the borrelial lipoprotein adhesins and their respective mutants, we propose the following Specific Aims: (1) Define the role of the fibronectin binding BBK32 in B. burgdorferi pathogenesis; (2) Further characterize the role of the decorin binding proteins in B. burgdorferi pathogenesis; and (3) Evaluate the importance of selected lipoproteins in the molecular pathogenesis of B. burgdorferi infections. We have genetically inactivated the fibronectin binding adhesin in an infectious isolate of B. burgdorferi and have strong preliminary evidence that fibronectin binding participates in secondary colonization and/or protects the organism against clearance. This mutant represents the first genetic knockout in a lipoprotein encoding loci that has a known adhesive activity that targets a mammalian ligand. Similar analyses are planned for the genes encoding the decorin binding protein adhesins as well as genetic studies to evaluate a panel of novel lipoproteins for their importance for borrelial pathogenesis. Following initial characterization studies using in vitro correlates of infection, i.e., adhesion and invasion, we will then determine the molecular mechanism(s) these adhesins use to colonize, disseminate, and/or persist within the infected mammalian host(s).